ON JULY 9TH, 1968, EIGHT white mice were placed into a strange box at the National Institute of Health in Bethesda, Maryland....The mice themselves were bright and healthy, hand-picked from the institute’s breeding stock. They were given the run of the place, which had everything they might need: food, water, climate control, hundreds of nesting boxes to choose from, and a lush floor of shredded paper and ground corn cob. This is a far cry from a wild mouse’s life—no cats, no traps, no long winters...The residents of Universe 25 were mostly left alone, save for one man who would peer at them from above, and his team of similarly interested assistants. They must have thought they were the luckiest mice in the world. They couldn’t have known the truth: that within a few years, they and their descendants would all be dead.